Laser mirror vision

ABSTRACT

The present invention relates to a method and an apparatus for determining a three dimensional image of the a moving object by means of reflecting means such as mirrors and a planar beam of light such as a laser light. As the object enters the light a two dimensional image of the object is captured, wherein the image comprises both the reflection of the beam of light from the object and also the reflection from the reflecting means. By transformation procedure a two dimensional image is transformed to a two dimensional object image and based on plurality of such images a three dimensional image is defined from which the volume can be calculated. This can be used to determine the weight distribution of the object, which is important for portioning.

This application is the U.S. national phase of international applicationPCT/IS02/00004 filed 1 Feb. 2002, which designated the U.S.

This application also claims the benefit of the filing date of U.S.provisional patent application Ser. No. 60/265,876, filed 5 Feb. 2001.

FIELD OF THE INVENTION

The present invention relates to a method and an apparatus fordetermining a three dimensional image of the a moving object by means ofreflecting means such as mirrors and a planar beam of light such as alaser light.

DESCRIPTION OF THE PRIOR ART

Determination of a three dimensional image of conveyed food items is animportant task for the food industry. When the processing comprisesgrading objects by form, size and weight, information regarding thevolume and the shape of the food item is necessary.

U.S. Pat. No. 5,184,733 describes a method and apparatus for determiningthe volume, form and weight of objects. A linescan camera records a topview of the object and at the same time records a profile view of theobject through a mirror positioned on a fixed support at the side of aconveyor. From these data the width and the height of the object isdetermined. Accordingly, the composition image of the object consists ofmany cross-sections, with the width and the maximum thickness of theobject being measured in each cross-section.

In U.S. Pat. No. 4,979,815 a range imaging system is presented for ofproducing a range image of an area of the surface of an object. This isutilized by projecting a substantially planar beam of light onto anobject surface to illuminate the surface along a light stripe. Theilluminated light beam is viewed and converted into an image generatingthe range image of the object. A 3-D image of the object is formed bymoving the object while it is scanned.

The problem with the solution describe in U.S. Pat. No. 5,184,733 is howinaccurate it is. By determining only the width and height of theobject, the errors can be very height, especially when the object hasirregular structure.

This problem is only partly solved in U.S. Pat. No. 4,979,815, byviewing illuminated light beam on the surface of the object. Bymeasuring only the top view and the profile image the volume estimationcan also be inaccurate, specially when the objects have a very irregularshape. By using a planar beam of light situated above the moving objectonly the visible part of the object facing the capturing means can bedetected, form which a two dimensional image will be formed. Parts ofthe object such as parts of the surface that is not in line of sightfrom the viewpoint of the capturing means as well as all the downwardlyfacing parts of the object will not be visible for the capturing meansas will therefore appear as blanks in the captured image. This causes anincrease in uncertainty in the measurement.

Accordingly, there is a need for further improvements in such volumedetermination of objects being moved.

GENERAL DESCRIPTION OF THE INVENTION

It is an object of the present invention to increase the accuracy in thedetermination of a three dimensional image of a moving object by meansof additionally detecting the areas of the object which are not visiblein the direct view.

According to the first aspect the present invention relates to a methodfor determining a three dimensional image of an object being conveyed bya moving means through a planar beam of light the method comprising thesteps of, repetitively

-   -   a) capturing a two dimensional image of the object with a        capturing means, the captured image comprising a scan element        based on a reflection of the planar beam of light from the        object and a scan element based on a reflection of the planar        beam of light from at least one reflecting means,    -   b) dividing the two dimensional image into at least two image        domains, wherein one image domain comprises a reflection of the        planar beam of light from the object and at least one image        domain comprises a reflection of the planar beam of light from        at least one reflecting means, and    -   c) transforming the image domains into a two dimensional mutual        object domain by means of a transformation procedure,

while the object is being subjected to the planar beam of light andbased on the plurality of the two dimensional image in the object domaina three dimensional image is defined.

The conveying means can be a conveyor belt and the planar beam of lightmay be a laser and a cylindrical lens or a vibrating mirror forproducing a planar beam of light, which is situated above the movingobject and wherein the plane of the beam light is perpendicular to themoving direction of the object. As the object enters the light, thelight is both reflected from the object to the capturing means, and fromthe reflecting means to the object, wherein the reflection comprises aplurality of scan elements. The frequency of capturing a two dimensionalimage could be controlled by a computer, wherein when no profile imageis detected the image processing is minimal and the scan frequency ismaximal, yielding maximal resolution for locating the edge of the objectthat first crosses the light. As soon as the object enters the light theamount of processing per scan line increases and the scan frequency canbe decreased or set to a desired value.

This image processing is repeated while the object is being subjected tothe planar beam of light. Based on a plurality of such two dimensionalimages in the object domain, a three dimensional image is defined andthe volume can be determined. By varying the processing rate theresolution of the three dimensional image is varied. High processingrate would lead to high resolution of the images and conversely. Byweighing the object the mass distribution can furthermore be determined.This is an important feature for batching, wherein the mass distributionis used for cutting the object in accordance to predefined criteria,wherein said criteria are based on the speed of the moving means and themass distribution.

Additional features can be determined, such as the roughness of thesurface of the object, wherein the irregularity of the contour line ofthe two-dimensional profile image is used as an indicator of theroughness, wherein a smooth surface is reflected in a irregular contourline. Furthermore, by capturing colours information regarding featuressuch as fat and muscle can be determined. The roughness, colour,reflectivity and light absorption may also be related to the conditionof the material such as porosity, chemical composition or water content.

The reflecting means may comprise at least one first side mirror, whichmay be positioned parallel to the moving direction of the object and inthe plane of the planar beam of light so that the side view image of theobject can be detected and at least one rear back mirror. In oneembodiment the number of said at least one first side mirrors is two,positioned parallel to the moving direction along with one rear backmirror situated at a location approximately opposite to the capturingmeans, on the other side of the light beam plane. The angle between theplane of the back mirror and the planar beam of light would be such thatthe reflection of the light which is reflected opposite to the capturingmeans to the back mirror would be captured by the capturing means. Thenumber of capturing means can however be different and is not restrictedto use of only one rear back mirror or only two side mirrors.

The side mirror enables viewing the side image parts of the object,which would otherwise not be detectable from the capturing means, suchas downwardly facing parts. On the other hand surface parts that are notin line of sight for the capturing means can be captured through therear back mirror. Therefore the images that the capturing means capturesis the reflection form the object, the reflected image from the sidemirror and the reflected image from the back rear window.

In order to increase the efficiency in the performance in the capturingmeans, such as the resolution, at least one second side mirror could besituated between the at least one first side mirror and the at least oneback rear mirror. In this embodiment the purpose of the at least onefirst side mirror is to reflect the laser beam underneath the side ofthe object towards the least one second side mirror. The at least onesecond side mirror would be positioned in such a way to decrease theviewing angle of the detecting means and therefore increase theperformance in the capturing means. Instead of capturing the side viewimage from the at least one first side mirror, the side view image willbe viewed in the at least one second side mirror and captured in thecapturing means.

One embodiment of such arrangement is to use two first side mirrors andtwo second side mirrors with only one back rear window, wherein thedistance between the two second side mirrors is shorter that between thefirst side mirrors which allows decreasing the viewing angle of thecapturing means.

Both these embodiments would preferably be assembled and mounted as oneunit in a fixed position, i.e. the light source, the capturing means andthe reflecting means.

The capturing means can for example be a matrix sensor, such as a CCD ora CMOS semiconductor sensor. The captured images are in an image domain,which does not give the preferable coordinates. By dividing the twodimensional image into at least two image domains, wherein one imagedomain comprises a single reflection of the planar beam of light fromthe object to the capturing means and at least one image domaincomprises a reflection of the planar beam of light from at least onereflecting means and by transforming them into a mutual object domainthe desirable capturing means coordinates can be obtained. Thetransformation procedure comprises transforming each scan element with atransformation function adapted for transforming that specific imagedomain into the mutual object domain. The transformation function cancomprise a translational, rotational, and/or scaling transformation.From the mutual object domain a two dimensional cross sectional profileof the image is obtained. By repeating this while the object is beingsubjected to the planar beam of light and based on the plurality of thetwo dimensional image in the object domain a three dimensional image isdefined. The transformation from the image domains to the mutual objectdomain can be based on database (look up tables, memory tables) whereinthe coordinates of the picture scan elements in the image domains aregiven new coordinates in accordance with said transformations to themutual object domain. This may result in higher processing speed than,for example, real-time transformation calculations. The database couldfor example be obtained in accordance to a specific setup in accordanceto the arrangement and location of the reflecting means, the lightsource and the detecting means relative to each other. If the relativelocation would change the relative distance could be changed inaccordance to the initial setup. The database could also automaticallybe updated if the internal position of the reflecting means, the lightsource and the detecting means would change, in accordance to areference system fixed to the capturing means.

According to another aspect the present invention relates to anapparatus for determining three-dimensional geometrical and surfaceinformation of a moving object, the apparatus comprising

-   -   conveyor for conveying the object while the processing occur,    -   an illumination source that casts a planar beam of light across        the object,    -   reflecting means for reflecting the light to the object and to        reflected light from the object,    -   capturing means for capturing the light reflected from the        object and the reflecting means,

the apparatus further comprising a control system being provided withprocessing means having stored therein a computer program wherein inputand output means and means for storing information are being adapted inorder to response to determine a three dimensional image, wherein thedetermination of the three dimensional image comprises

-   -   means for repetitively capture two dimensional images from the        reflecting means and the object,    -   means for repetitively transforming the two dimensional captured        images from a image domain into a object domain, from which a        three dimensional image is determined.

DETAILED DESCRIPTION OF THE INVENTION

In the following the present invention, and in particular preferredembodiments thereof, will be described in greater details in connectionwith the accompanying drawings in which

FIG. 1 a)–FIG. 1 b) shows a perspective view of the apparatus accordingto the present invention,

FIG. 2 shows an overview of the apparatus from the detecting means pointof view wherein the object is a cylinder,

FIG. 3 shows image domains and transformation from the image domains toa mutual object domain for a cylinder,

FIG. 4 shows an overview of the apparatus from the detecting means pointof view wherein the object is a cone shaped object,

FIG. 5 shows a image domains and transformation from the image domainsto a mutual object domain for the cone shaped object,

FIG. 6 shows a overview of the cone shaped object,

FIGS. 7 a) and 7 b) shows two perspective views for a cone shaped objectafter repeating the image processing of the two dimensional image whilethe object enters the planar beam of light,

FIG. 8 shows a Flow Diagram from when the object enters until the objectleaves the planar beam of light,

FIG. 9 shows a preferred embodiment of the invention where twoadditional side mirrors have been added to the two first side mirrors.

In FIGS. 1 a) and 1 b) a perspective view of the apparatus according tothe present invention is shown, wherein an object 2 is being conveyed bymeans of conveyor belt 1 in a direction given by the arrow. Illuminationsource 5 casts a planar beam of light 10 across the conveyer belt andorthogonal to the direction of movement and further on the two sidereflecting means 4, preferably mirrors. The illuminating source may be alaser and a cylindrical lens or vibrating mirror for producing a planarbeam of light. A capturing means 6 such as a CCD matrix sensor issituated above the conveyor belt and receives a view of practically theentire perimeter through the two reflecting side mirrors, which in thisembodiment are left-and right mirrors as shown in FIG. 1 b and the backrear window 3. The orientation of the sensor and the left-and rightmirrors is such that that the sensor captures the following four views:

-   a. The surface of the object where it crosses the plane of the    illumination line.-   b. A left mirror view of the side of the object.-   c. A right mirror view of the side of the object.-   d. A back rear window view from the surface of the object, which may    otherwise not be visible in the direct view. This fourth view fills    therefore into the blanks that would otherwise occur if it would not    be placed there.

FIG. 2 shows an example of an cylindrical shaped object 9 being conveyedfrom the viewpoint of the capturing means at one instant of time. Shownis the reflected image from the first two side mirrors 4, a right sideimage 11 and left side image 12, the rear back mirror image 13 andreflection from the object 14 as the object enters the planar beam oflight 10. The side mirrors serve the purpose that they reflect theillumination line to the sides of the object and to underneath segmentsthat are elevated from the conveyor belt surface and give therefore thesensor a view of these areas. As FIG. 2 shows, half the perimeter of thecylinder is visible, and the other half is detected by the side mirrors.Therefore, the light that hits the surface of the cylinder that is inline of sight from the viewpoint of the capturing means is reflected tothe sensor. If on the other hand a part of the surface would not bereflected to the sensor, the use of the back mirror would be preferable.

FIG. 3 shows an image domain, wherein the images from each reflectingmeans are assigned to a certain domains. The image 12 of the left mirroris assigned to one domain 15, the image 11 of the right mirror isassigned to another domain 17, the image 13 of the back mirror isassigned to the third domain 16 and the image 14 that is reflected tothe sensor is assigned to the fourth domain 18. Each of these capturedimages comprises scan elements, i.e. pixels, based on a reflection ofthe planar light beam from the object and the mirrors. These scanelements in each domain have a coordinate in accordance with the domainthat it is assigned to. By transforming each domain to a mutual objectdomain by means of transforming procedure 19, a two dimensional imagecan be defined 20 in a object domain. The transformation procedure cancomprise translational, rotational and/or scaling transformation of thematrix elements from the image domain into the object domain. Thetransformation from the image domain to the mutual object domain can bebased on a database, wherein the coordinates of the picture scanelements in the image domain are given new coordinates in accordancewith said transformations to the mutual object domain. Thetransformation procedure may also comprise a transformation from theimage domains into the object domain without using a database, whereinthe transformation can be based on the orientation of the referencepoints relative to the capturing means. For this object, the back rearmirror was not essential because of the reflection toward the capturingmeans.

After object domain is obtained, endpoints in fourth domain 18 aftertransformation are obtained and shortest distance to each said endpointto each transformed endpoints in domain 15 and 17 define matching pointsand are used to connect the object together. The area for the object canbe calculated by summation after these matching points have been found.

The area determination is preferably based on summing up the area of onepixel, which is the width multiplied by the height of the pixel. Volumeis therefore obtained by multiplying said area with the image thickness,which depends on the resolution.

Due to limited resolution triangulation method may be used between eachheight pixel to minimize the volume error.

This image processing is repeated while the object is being subjected tothe planar beam of light. Based on a plurality of such two dimensionalimages in the object domain, a three dimensional image is defined. Byvarying the processing rate the resolution of the three dimensionalimage is varied. High processing rate would lead to high resolution ofthe images and conversely.

FIG. 4 shows an example of an conical object 21 being conveyed, whereinthe end with the larger radius is facing the sensor. Shown is thereflected image from the left side mirror 23, the right side mirror 22and the back mirror 24. In FIG. 5 image domains from each reflectingmeans are shown. As before the image of the left mirror 23 is assignedto one domain 15, the image of the right mirror 22 is assigned toanother domain 17, the image of the back mirror 24 is assigned to thethird domain but due to the conical shape of the object the image domainof the direct view to the sensor 18 is empty, where we have assumed thatno reflection from the surface is detected directly by the sensor. Inthis case the role of the back mirror is necessary in order to enable adefinition of the two dimensional image in the object domain. Thetransformation procedure 25 from the image domains to the mutual objectdomain would therefore define the object. By repeating the imageprocessing a plurality of two dimensional image in the object domainwould define a three dimensional image.

FIG. 6 shows a side view of the conical object 21 shown in FIG. 5 as itis being conveyed 1. As the object enters the planar beam of light 10from the light source 5, the processing start. No light is reflectedfrom the object to the sensor 6. However, from the back mirror 3, thesurface of the object can be detected from the reflection from thesurface from the object to the back mirror 3, and from the back mirrorto the sensor. Therefore half the perimeter of the object is detected bythe back mirror and the other half by the side mirrors 4. By means oftransformation procedure, a processor 7 is used to transforme the datafrom the image domains to a mutual object domains.

FIGS. 7 a) and 7 b) shows two perspective views for a conical shapedobject after repeating the image processing of the two dimensional imagewhile the object enters the planar beam of light. The result is a numberof cylinders wherein the radius increases in discrete steps from thelowest diameter 37 up to the highest diameter 36. FIG. 7 a) shows anexample of two different processing speeds, which is reflected indifferent height of the cylinder 32, 31. As the processing speed isincreased, the accuracy of the volume determination of the objectincreases 28 and the height of each cylinder decreases 32, compared tolower processing speed, where the height of each cylinder is larger 31.The front view in FIG. 7 b) shows a number of cylinders with diametersD₁ and height d₁, wherein the height d_(i) (32,31) is directly relatedto the processing speed. Accordingly, the diameter of the first circle37 corresponds to the minimum height in FIG. 7 a) 37 and the radius ofthe largest circle 36 corresponds to the maximum height.

FIG. 8 shows a Flow Diagram from an object entering a planar beam oflight until the it leaves the planar beam of light. Initially, theamount of processing is minimal and thus the scan frequency can bemaximal. In this moment the image may consist of a straight line untilthe object enters the light. Then as soon as the object enters theplanar beam of light 10, the processing speed increases and the scanningfrequency can be decreased to a set value as the capturing of twodimensional images in a image domain starts 38. A processor transformsthe data from image domain where the images are captured to an objectdomain 39 which forms a two dimensional image. This is repeated whilethe object enters the light 40. Soon as the object does not subject thelight, a complete 3D image in the object domain can be constructed.

FIG. 9 shows an example of the most preferably embodiment of theinvention where two additional second side mirrors 42,43 have been addedto the two first side mirrors 22,23. The distance between the two secondside mirrors is shorter than between the first two side mirror. By usingsuch arrangement the viewing angle of the capturing means is lowered andthe efficiency in the performance in the capturing means is increased.Furthermore the capturing means can be positioned closer to thereflecting means and the light source. The two second side mirrors willfurthermore be positioned so that the side view image of the object fromthe two first side mirrors is viewed in the two second side mirrors44,45, from which it is captured by the capturing means.

1. A method for determining a three dimensional image of a movingobject, the method comprising the steps of, repetitively: capturing atwo dimensional image of the object with a capturing means, the capturedimage comprising a scan element based on a reflection of a planar beamof light from the object and a scan element based on a reflection of theplanar beam of light from the object, further reflected from a pluralityreflecting means, dividing the two dimensional image into at least twoimage domains, wherein one image domain comprises a reflection of theplanar beam of light from the object and at least one image domaincomprises a reflection of the planar beam of light from the at least onereflecting means, and transforming the image domains into a twodimensional mutual object domain by means of a transformation procedure,while the object is being subjected to the planar beam of light andbased on the plurality of the two dimensional images in the objectsdomain, defining a three dimensional image, and storing the images in acomputer system, wherein the reflecting means comprise at least one sideand at least one back mirror adapted to view side and top image parts ofthe object, and wherein the mutual object domain gives the coordinatesof the two dimensional cross sectional profile of the image.
 2. Themethod according to claim 1, wherein the transformation of the imagedomains into a mutual object domain comprises transforming each scanelement in the image domain with a transformation function adapted fortransforming that specific image domain into the mutual object domain.3. The method according to claim 1, wherein the transformation functioncomprises translational transformation.
 4. The method according to claim1 wherein the transformation function comprises rotationaltransformation.
 5. The method according to claim 1 wherein thetransformation function comprises scaling transformation.
 6. The methodaccording to claim 1, wherein the planar beam of light is situated abovethe moving object and wherein the plane of the beam light isperpendicular to the moving direction of the object.
 7. The methodaccording to claim 1, wherein the reflecting side of said at least oneback mirror is positioned perpendicular to the moving direction of theobject.
 8. The method according to claim 1, wherein said at least oneside mirror is positioned parallel to the moving direction of theobject.
 9. The method according to claim 1, wherein the light source,the capturing means, said least one side mirror and said least one backmirror are assembled and mounted as a one unit in a fixed position,wherein said at least one first side mirror is situated between thecapturing means and said at least one back mirror.
 10. The methodaccording to claim 1 wherein the moving means is a conveyor belt.
 11. Amethod for determining a three dimensional image of a moving object, themethod comprising the steps of, repetitively: capturing a twodimensional image of the object with a capturing means, the capturedimage comprising a scan element based on a reflection of a planar beamof light from the object and a scan element based on a reflection of theplanar beam of light from the object, further reflected from a pluralityreflecting means, dividing the two dimensional image into at least twoimage domains, wherein one image domain comprises a reflection of theplanar beam of light from the object and at least one image domaincomprises a reflection of the planar beam of light from the at least onereflecting means, and transforming the image domains into a twodimensional mutual object domain by means of a transformation procedure,while the object is being subjected to the planar beam of light andbased on the plurality of the two dimensional images in the objectsdomain, defining a three dimensional image, and storing the images in acomputer system, wherein the reflecting means comprise at least one sideand at least one back mirror adapted to view side and top image parts ofthe object, and wherein the transformation from the image domains to themutual object domain, is based on database wherein the coordinates ofthe picture scan elements in the image domains are given new coordinatesin accordance with said transformations to the mutual object domain. 12.A method for determining a three dimensional image of a moving object,the method comprising the steps of, repetitively: capturing a twodimensional image of the object with a capturing means, the capturedimage comprising a scan element based on a reflection of a planar beamof light from the object and a scan element based on a reflection of theplanar beam of light from the object, further reflected from a pluralityreflecting means, dividing the two dimensional image into at least twoimage domains, wherein one image domain comprises a reflection of theplanar beam of light from the object and at least one image domaincomprises a reflection of the planar beam of light from the at least onereflecting means, and transforming the image domains into a twodimensional mutual object domain by means of a transformation procedure,while the object is being subjected to the planar beam of light andbased on the plurality of the two dimensional images in the objectsdomain, defining a three dimensional image, and storing the images in acomputer system, wherein the reflecting means comprise at least one sideand at least one back mirror adapted to view side and top image parts ofthe object, and wherein the at least one back mirror is a single rearback mirror situated opposite the capturing means and above the movingobject.
 13. A method for determining a three dimensional image of amoving object, the method comprising the steps of, repetitively:capturing a two dimensional image of the object with a capturing means,the captured image comprising a scan element based on a reflection of aplanar beam of light from the object and a scan element based on areflection of the planar beam of light from the object, furtherreflected from a plurality reflecting means, dividing the twodimensional image into at least two image domains, wherein one imagedomain comprises a reflection of the planar beam of light from theobject and at least one image domain comprises a reflection of theplanar beam of light from the at least one reflecting means, andtransforming the image domains into a two dimensional mutual objectdomain by means of a transformation procedure, while the object is beingsubjected to the planar beam of light and based on the plurality of thetwo dimensional images in the objects domain, defining a threedimensional image, and storing the images in a computer system, whereinthe reflecting means comprise at least one side and at least one backmirror adapted to view side and top image parts of the object, andwherein the at least one side mirror is positioned along to the movingdirection of the object and in the plane of the planar beam of light sothat light is reflected from the mirror to the object and back to themirror thereby allowing the side view image of the object which areotherwise not detectable by the capturing means to be detectable.
 14. Amethod for determining a three dimensional image of a moving object, themethod comprising the steps of, repetitively: capturing a twodimensional image of the object with a capturing means, the capturedimage comprising a scan element based on a reflection of a planar beamof light from the object and a scan element based on a reflection of theplanar beam of light from the object, further reflected from a pluralityreflecting means, dividing the two dimensional image into at least twoimage domains, wherein one image domain comprises a reflection of theplanar beam of light from the object and at least one image domaincomprises a reflection of the planar beam of light from the at least onereflecting means, and transforming the image domains into a twodimensional mutual object domain by means of a transformation procedure,while the object is being subjected to the planar beam of light andbased on the plurality of the two dimensional images in the objectsdomain, defining a three dimensional image, and storing the images in acomputer system, wherein the reflecting means comprise at least one sideand at least one back mirror adapted to view side and top image parts ofthe object, and wherein the frequency of capturing a two dimensionalimage is controlled by the capturing means in a way that when no profileimage is detected the image processing is minimal and the scan frequencyis maximal.
 15. A method for determining a three dimensional image of amoving object, the method comprising the steps of, repetitively:capturing a two dimensional image of the object with a capturing means,the captured image comprising a scan element based on a reflection of aplanar beam of light from the object and a scan element based on areflection of the planar beam of light from the object, furtherreflected from a plurality reflecting means, dividing the twodimensional image into at least two image domains, wherein one imagedomain comprises a reflection of the planar beam of light from theobject and at least one image domain comprises a reflection of theplanar beam of light from the at least one reflecting means, andtransforming the image domains into a two dimensional mutual objectdomain by means of a transformation procedure, while the object is beingsubjected to the planar beam of light and based on the plurality of thetwo dimensional images in the objects domain, defining a threedimensional image, and storing the images in a computer system, whereinthe reflecting means comprise at least one side and at least one backmirror adapted to view side and top image parts of the object, andwherein from the three dimensional image the total volume of the objectis calculated.
 16. A method for determining a three dimensional image ofa moving object, the method comprising the steps of, repetitively:capturing a two dimensional image of the object with a capturing means,the captured image comprising a scan element based on a reflection of aplanar beam of light from the object and a scan element based on areflection of the planar beam of light from the object, furtherreflected from a plurality reflecting means, dividing the twodimensional image into at least two image domains, wherein one imagedomain comprises a reflection of the planar beam of light from theobject and at least one image domain comprises a reflection of theplanar beam of light from the at least one reflecting means, andtransforming the image domains into a two dimensional mutual objectdomain by means of a transformation procedure, while the object is beingsubjected to the planar beam of light and based on the plurality of thetwo dimensional images in the objects domain, defining a threedimensional image, and storing the images in a computer system, whereinthe reflecting means comprise at least one side and at least one backmirror adapted to view side and top image parts of the object, andwherein, by weighing the object and by using information relating to atotal volume of the object, a mass distribution is determined.
 17. Amethod for determining a three dimensional image of a moving object, themethod comprising the steps of, repetitively: capturing a twodimensional image of the object with a capturing means, the capturedimage comprising a scan element based on a reflection of a planar beamof light from the object and a scan element based on a reflection of theplanar beam of light from the object, further reflected from a pluralityreflecting means, dividing the two dimensional image into at least twoimage domains, wherein one image domain comprises a reflection of theplanar beam of light from the object and at least one image domaincomprises a reflection of the planar beam of light from the at least onereflecting means, and transforming the image domains into a twodimensional mutual object domain by means of a transformation procedure,while the object is being subjected to the planar beam of light andbased on the plurality of the two dimensional images in the objectsdomain, defining a three dimensional image, and storing the images in acomputer system, wherein the reflecting means comprise at least one sideand at least one back mirror adapted to view side and top image parts ofthe object, and wherein a mass distribution is used for cutting theobject.
 18. A method for determining a three dimensional image of amoving object, the method comprising the steps of, repetitively:capturing a two dimensional image of the object with a capturing means,the captured image comprising a scan element based on a reflection of aplanar beam of light from the object and a scan element based on areflection of the planar beam of light from the object, furtherreflected from a plurality reflecting means, dividing the twodimensional image into at least two image domains, wherein one imagedomain comprises a reflection of the planar beam of light from theobject and at least one image domain comprises a reflection of theplanar beam of light from the at least one reflecting means, andtransforming the image domains into a two dimensional mutual objectdomain by means of a transformation procedure, while the object is beingsubjected to the planar beam of light and based on the plurality of thetwo dimensional images in the objects domain, defining a threedimensional image, and storing the images in a computer system, whereinthe reflecting means comprise at least one side and at least one backmirror adapted to view side and top image parts of the object, andwherein the purity of contour line obtained from the two-dimensionalprofile image of the object is used as an indicator for the surfaceroughness of the object.
 19. A method for determining a threedimensional image of a moving object, the method comprising the stepsof, repetitively: capturing a two dimensional image of the object with acapturing means, the captured image comprising a scan element based on areflection of a planar beam of light from the object and a scan elementbased on a reflection of the planar beam of light from the object,further reflected from a plurality reflecting means, dividing the twodimensional image into at least two image domains, wherein one imagedomain comprises a reflection of the planar beam of light from theobject and at least one image domain comprises a reflection of theplanar beam of light from the at least one reflecting means, andtransforming the image domains into a two dimensional mutual objectdomain by means of a transformation procedure, while the object is beingsubjected to the planar beam of light and based on the plurality of thetwo dimensional images in the objects domain, defining a threedimensional image, and storing the images in a computer system, whereinthe reflecting means comprise at least one side and at least one backmirror adapted to view side and top image parts of the object, andwherein the capturing means comprises means for capturing colour andwherein the colour is used as an indicator for fat content and/or musclecontent and/or water content and/or chemical composition.
 20. Anapparatus for determining a three dimensional image of an moving object,the apparatus comprising: a conveyor for conveying the object aplurality of reflecting means, capturing means for capturing a twodimensional image of the object while the object is being conveyed, thecaptured image comprising a scan element based on a reflection of aplanar beam of light from the object and a scan element based on areflection of the planar beam of light from the object, furtherreflected from the reflecting means, a computer system for storing thecaptured images and for dividing the two dimensional image into at leasttwo image domains, wherein one image domain comprises a reflection ofthe planar beam of light from the object and at least one image domaincomprises a reflection of the planar beam of light from the least onereflecting means and for transforming the image domains into a twodimensional mutual object domain by means of a transformation procedurewhile the object is being subjected to the planar beam of light andbased on the plurality of the two dimensional images in the objectdomain generating a three dimensional image of the object, wherein thereflecting means comprises at least one side and at least one backmirror adapted to view side and top image parts of the object, andwherein the mutual object domain gives the coordinates of the twodimensional cross sectional profile of the image.
 21. A method fordetermining a three dimensional image of a moving object, the methodcomprising the steps of, repetitively: capturing a two dimensional imageof the object with a capturing means, the captured image comprising ascan element based on a reflection of a planar beam of light from theobject and a scan element based on a reflection of the planar beam oflight from the object, further reflected from a plurality reflectingmeans, dividing the two dimensional image into at least two imagedomains, wherein one image domain comprises a reflection of the planarbeam of light from the object and at least one image domain comprises areflection of the planar beam of light from the at least one reflectingmeans, and transforming the image domains into a two dimensional mutualobject domain by means of a transformation procedure, while the objectis being subjected to the planar beam of light and based on theplurality of the two dimensional images in the objects domain, defininga three dimensional image, and storing the images in a computer system,wherein the reflecting means comprise at least one side and at least oneback mirror adapted to view side and top image parts of the object, andwherein the mass distribution is used for cutting the object inaccordance to predefined criteria, and wherein said criteria is based onthe speed on the moving means and the mass distribution.